黑磷-石墨混合物作为锂离子调节器实现稳定的锂沉积

A black phosphorus-graphite hybrid as a Li-ion regulator en-abling stable lithium deposition

锂金属(Li)负极因其高比容量和低氧化还原电位而被认为是高能量密度锂二次电池最有应用前景的候选材料。然而,锂金属在电池循环过程中的不均匀沉积导致的锂枝晶问题严重阻碍了锂金属负极的实际应用。本文将黑磷-石墨(BP-G)混合物引入作为锂金属负极的人工保护层。具有亲锂性的二维少层黑磷与具有高电子电导的石墨相结合,可以作为离子调节器来调节锂离子的迁移,从而实现均匀稳定的锂沉积。由于锂枝晶的生长受到抑制,锂金属在Li||Cu半电池中的库仑效率在500多个循环中达到>98.5%;在Li||Li对称电池中,极化电压保持在<50 m V,循环寿命达到2000 h以上。此外,带有BP-G锂离子调节器的LiFePO_(4)(LFP)||Li全电池比未修饰的锂金属负极电池具有更高的比容量和更好的循环稳定性。因此,BP-G锂离子调节器的引入被证明是实现可充电锂金属电池稳定锂沉积的有效方法。

Lithium(Li)metal anodes have been regarded as the most promising candidates for high energy density second-ary lithium batteries due to their high specific capacity and low redox potential.However,the issues of Li dendrites caused by nonuniform lithium deposition during battery cycling severely hinder the practical applications of Li metal anodes.Herein,a hybrid of black phosphorus-graphite(BP-G)is introduced to serve as an artificial protective layer for the Li met-al anode.The two-dimensional few-layer BP,which is lithophilic,combined with the high electronic conductive graphite can act as a regulator to adjust the migration of Li ions,delivering a uniform and stable lithium deposition.As the growth of lithium dendrites is inhibited,the utilization of Li metal achieves>98.5%for over 500 cycles in Li‖Cu half cells,and the life span is maintained over 2000 h in Li‖Li symmetric cells with a low voltage hysteresis of 50 mV.Moreover,the LiFePO_(4)‖Li full cell with a BP-G Li-ion regulator presents significantly better specific capacity and cycling stability than that with the bare Li metal anode.Therefore,the introduction of the BP-G Li-ion regulator is demonstrated to be an effect-ive approach to enable stable lithium deposition for rechargeable Li metal batteries.